1. Field of the Invention
The current invention relates to leadscrew systems, and more specifically but not exclusively, to leadscrew systems including nut assemblies.
2. Description of the Related Art
A leadscrew is a screw, or threaded rod, that may be used, in conjunction with a corresponding nut, to convert rotational motion into linear motion. In a typical leadscrew system, such as ones sold by Haydon Kerk Motion Solutions of Waterbury, Conn., a leadscrew is coupled to a motor that rotates the leadscrew. As the leadscrew rotates, the corresponding nut, which is screwed onto the leadscrew and also connected to a guide rod, moves up or down along the leadscrew shaft. The direction of the nut's linear motion depends on the leadscrew's direction of rotation and thread characteristics.
FIG. 1 shows a simplified side view of leadscrew system 100 comprising leadscrew 101, motor 102, corresponding screw nut 103, guide rod 104, collar 105, connecting strut 106, and support base 107. Motor 102 and guide rod 104 are rigidly attached to support base 107. Leadscrew 101 is (i) parallel to guide rod 104 and (ii) connected to motor 102 so as to be rotated by motor 102 relative to base 107, as indicated by rotational directions 101a and 101b. The thread of screw nut 103 complements the thread of leadscrew 101. The materials of leadscrew 101 and screw nut 103 are such as to allow them to have relatively low-friction interaction and, consequently, allow leadscrew system 100 to have relatively efficient translation of the rotational motion of leadscrew 101 into corresponding linear motion of screw nut 103. The materials and shape characteristics of rail guide 104 and collar 105 are such that collar 105 can slide along guide rod 104 with relatively low friction. Collar 105 may comprise a bearing or a guide. Connecting strut 106 rigidly connects screw nut 103 to collar 105 so that screw nut 103 does not rotate when leadscrew 101 rotates, but, instead, screw nut 103 moves linearly along leadscrew 101. This allows for relatively precise control of the linear motion and placement of screw nut 103 relative to base 107.
If leadscrew 101 rotates in direction 101a, then screw nut 103, along with strut 106 and collar 105, moves up (away from base 107), while, if leadscrew 101 rotates in opposite direction 101b, then screw nut 103, along with strut 106 and collar 105, moves down (toward base 107). Note that the materials and thread characteristics of leadscrew 101 and screw nut 103 may be such that screw nut 103, if it were not attached to strut 106 and collar 105, would both rotate around leadscrew 101 (in direction 101a) and move down (toward base 107) when motor 102 is not rotating leadscrew 101, merely from the effects of gravitational pull on screw nut 103 towards base 107.